Hey there guys, this is my second post here. I already posted a draft for a Joke SCP (which you can still see in the other tab) and was doing some reading to improve it when this idea popped into my mind and just wouldn't let go, so I figured I might just as well write it down. I'm about to enter exam season in college so I wanted to leave this one gathering feedback as well so I have something to work out with later on.
A couple of things I wanted to point out:
1) It's freaking long. I know. I really went out of control here. If you have any suggestions on how to summarize it a bit more they are very much welcome.
2) English is not my native tongue. I've been using it for a long time so I can handle myself pretty good but I know I can't hold a candle against a real native. So if you see any grammar or spelling errors, again, please do point out.
3) I'm really new to the wiki interface, so I can't add much content yet. I figured out the tabs and a couple more things but still it looks pretty desolate. If you have any suggestions about styling, much obliged.
Other than that, hope you like it. Please come on blunt with it so I can get better at this, I'd really like to. Here's the link: http://scpsandbox2.wikidot.com/warlynx

Okay, first off, it'll look more approachable if you have proper spacing. I'm an admin on the sandbox site, so I'll fix that up for you right now. In the future, if you're unsure about how to code something, ask people for help and give permission for fixes (because we take sandbox vandalism very seriously, we need to confirm author consent for non-authors editing their page).

Since you mentioned that you're not a native English speaker, I'll focus on concept and not spelling/grammar since, uh… there's misspellings like "asbsolutely" and "percieves" and a ton of phrases that don't read entirely fluently. (Also, only use "it's" if you can replace the word with "it is".) That kind of stuff can wait until you've tightened up the concept a bit though, since there's no point in getting too worked up over grammar if the content is going to change.

First off, the containment can definitely use some trimming. You've got experimental info and containment breach info in there when pretty much all that's needed is the first two sentences. Also, some people don't like cross-outs because they believe that the Foundation would use digital records, in which case old information would be simply replaced rather than crossed out. Also, don't refer to an individual as a "subject" unless they're actually part of an experimental research design in which they are subjected to some sort of condition. Otherwise, they're not a subject, and/or it seems like the sentence only applies in experimental conditions (which is pretty much always not the case). Stuff like:

Said researchers must not attempt to cut ahead in line, use the bathroom or anything that could cause distress to the awaiting subjects.

can be shortened down to "Researchers must take care not to cause the individuals distress." We don't need to know that they can't use the bathroom; that's kind of extraneous text that just bogs down the entire section.

Regarding the description, I feel like it's way more complicated than it needs to be. Have the entire mouse designated as SCP-XXXX, and the little black box thing SCP-XXXX-1. If the outer casing is largely non-anomalous except for the custom design (which in itself doesn't carry any anomalous properties) then there's no need to put in the extra info about what's not interesting about it. Just say that the mouse has been adapted to use SCP-XXXX-1 as a power source, and move on to discuss what the mouse can do. (Also, "different languages (including braille)" is kind of vague. How many different languages? What kind of braille?)

Overall… I can't say I found this too interesting, sorry. I had a lot of questions like "what if someone uses the mouse for unconventional things, like a back massage or playing catch? What if the activity requires two people? What if there's no way to determine how bored/excited someone is, and they're just impartial towards the activity they use the mouse for?" And my main issue was "how did the Foundation figure out all this information anyway?" Keep in mind that as the author, you know the entire story, but the Foundation needs to have discovered what it knows about the SCP through observation and experimentation. How would someone with no prior knowledge whatsoever of the object, using only experimentation and observation, come to all the conclusions you've got in the article?

So you know, the "it makes you crazy until dead" approach isn't particularly interesting on its own anymore, given how many times SCPs with that effect have been written. Take a look at the articles tagged with "compulsion". Furthermore, the SCP's effect forcing someone to do something tends to be a bit of a lame narrative, since things are more interesting if there's a struggle involved, and/or if the people instead do terrible things of their own volition. Consider reading through the further discussion on the narrative issues of compulsion and addiction effects.

I stopped reading before the addenda. It just seemed like stuff I'd already seem before, with a conceptual basis that has been played out in the past few years. I suggest getting the idea improved in the Ideas and Brainstorming forum before you try to fix the draft.

All right, I'll give it a shot. My idea was later on to add an experimentation log to show how the concept had been evolving over time, but I didn't want to do it until I was sure it was coming out fine, which seems it was the right call.
I have an exam next week and then I'll give it another shot. Based on what you said reminded me I had an early thought of something similar but on a webpage that allowed you to send bureaucratic trash to someone you knew. I ended up choosing this approach instead but if like you just said it's something over-used perhaps it would be best to go back to the first idea from scratch.
Let me know what you think later on, thanks!!